Television system



b- 1938- v. K. ZWORYKIN TELEVISION SYSTEM Original Filed Aug. 5, 1952 3 Sheets-Sheet l INVIENTOR v. K. ZWORYKIN mfg/$41M ATTORNEY Feb. 8, 1938. v. K. ZWORYKIN I TELEVISION SYSTEM Original Filed Aug. 5, 1932 3 Sheets-Sheet 2 INVENTOR v. K. ZWORY N BY M ATTORNEY Feb. 8, 1938.

V. K. ZWORYKIN TELEVISION- SYSTEM Original Filed Aug. 5, 1932 3 Sheets- Sheet 3 may r05: 5

lllllll mi lik 79 INVENTOR v. K. zwoRvKm ATTORNEY Patented Feb. 8, 1938 UNITED STATES PATE NT OFFICE.

TELEVISION sY's'rsM' Vladimir K. Zworyk in, Philadelphia, 1a., assignor to Radio Corporation of ration oi Delaware Application August 5, 1932, Serial No.

Renewed September 12, 1936- 13 Claims.

The present invention relates to television receiving systems and is directed particularly to television receiving systems for reproducing stereoscopic television images.

It has been known for many years in' physics that in order to produce a stereoscopic or relief type image which is intended to show depth, it is necessary to look with each eye upon two separate pictures which were taken with the objec tive lenses ofthe viewing mechanism separated' by approximately the same separation as that ,of the human eyes. Various other separations may be used, depending upon the optical systems being utilized and depending upon the losses encountered therein, so long as the net result is substantially the equivalent of the aforementioned separation. It is customary in viewing stereo V seopic pictores to use a double optical system.

In the prior art the above principles were applied to television where stereoscopic images were a continuation in part, disclosed a television view-' ing cabinet in which a cathode ray tube; or similar image reconstructing "device, has been so arranged as tov be mounted within a cabinet and, when activated by received signals, produce a television image which appears on a plane at ninety .degrees to the desired viewing plane. By means of a lid provided for the receiving cabinet-and a-refiecting medium carried within, the lid, it has been found possible to position the reflector at such an angle that the reconstructed image could be viewed in the desired plane in the reflecting medium by an observer and remain visible throughout a wide angle. In the aforementioned" copending application I also disclosed a self-contained sound and television system, and it is to be understood that the present invention is intendedto embody all of the details of my above named copending ap-' plication with such additional. new details as are found in the present specification.

It' is a primary object of the present invention to simplify stereoscopic television and to avoid the I use of any optical systems for viewing the stereoscopic television picture.

Another object of the invention is to provide a stereoscopic television system wherein the image cz'tsss signals are produced either by purely electrical scanning aparatus or by the'so-called-mechanical scanning devices and to produce a system where- America, a corpo l in the image signals from the two or more independent scanning devices used at the transmitting point to produce the stereoscopic effects are coordinated one with the other in such manner that successive scannings of adjacent elemental strips of the subject of which the image is to be produced are coordinated both in'time and position definitely with the proper scanning device to produce the desired effects. s

Other objects of the invention are to provide a self-contained receiver system for television which is compact, pleasing in appearance, capable of being viewed through a wide angle, responsive to both stereoscopic and ordinary television signals and efficient in use and operation.

, Other objects of the invention-will, of course,

I appear and vbecome more apparent from reading the following specification and claimsin connection with the accompanying drawings, wherein:

Figfl shows a conventional arrangement by which the image as viewed is'so screenedth'at alternate sections are observable;

Fig. 2 shows one-form of viewing arrangement by whichthe stereoscopic image is viewed;

Fig. 3 illustrates a suitable form of circuit arrangement to control separate-scanning tubes;

Fig. 4 is a schematic showing on a considerably enlarged scale of a section of the pattern traced by the plurality of scanning or elimination devices;

Fig. 5 is a modification of the pattern of Fig.

v4 at the transmitting end of the system;

Fig. 6 illustrates diagrammatlcally'the wave form of the signals transmitted with the arrangement ofFig.5;" a

V Fig.'7 graphically illustrates the wave forma.-. tion and control of the separate scanning tubes shown by Fig. 3 and in this figure portions la and ,lb illustrate the alternate operation of the two scanning tubes of Fig. 3 and the portions 1c .and Id illustrate the alternate deflection of the scanning ray with the arrangement of Fig. 3;

Fig. 8 is a mechanical system for scanning or reproducing images in the present invention;

Fig.4) diagrammatically indicates a suitable connection of one of the transmitter tubes of Fig.

3 with'the transmitter, and from this showing it will be understood that the other scanning tube is similarly arranged, as has beenconventiorially in-' dicated; and,

Fig. '10 illustrates a suitable receiving system using-a cathode ray tube as the image recon structing the image, it is also possible to re-form the picture from two series of lines alternating with each other which serve to give the efiect of depth to the produced images. The method by which this image reconstruction is accomplished .,forms a part of the present invention in so far as it cooperates with the arrangement shown at the receiving point for reproducing the pictures so constructed. I

.As was indicated inthe foregoing paragraphs,

' the stereoscopic picture may be transmitted in several different" ways. One suitable transmitter arrangement is to provide two cathode ray tubes so arranged that each observes, so to speak,- the subject from separate points which are spaced I apart a distance comparable to the separation of the human eyes for example, about 2 inches, and are then .so arranged as to scan thesubject with each tube in such manner that alternate lines are scanned by alternate tubes. With such a system the deflecting. flelds serving to control the cathode ray pencil ,within the tube' are produced from a single'source as has been indicated by Fig. 3 and through appropriate control systems function alternately upon each tube in a such manner that one tube scans one line and then becomes inoperative to scan during the period required for scanning an adjacent line,

whereas the other scanning tube operates exactly opposite so that while the first tube is operative the second tubeis inoperative, and when the second tube is operative the first tube is inoperative and soon. Other suitable scanning systems function somewhat similarly as will be apparent from the description which is'to follow.

. For transmitting a signal to the various points of reception the varying intensity of light and shadow are resolved into appropriate image cur.-

rent signals which-are used to modulate a suitable generator carrier frequency which is transmitted. by wire or radio to each receiving point.-

To analyze briefly the arrangement of my present apparatus at the receiving end of the' system, towhich this inventionis directed primarily, the two sets of stereoptic images are produced upon the fluorescent'screen ofa cathode ray tube, and, in contrast to the usual method of reception for ordinary pictures by which the image intensities represented in the fluorescent end wall of a cathode ray tube would be visible throughout a wide angle in the mirror surface carried on the inside cover of the cabinet lid of the arrangement described in my above named application, the present arrangement is so de signed that the lines along which the image appears to be reconstructed apparently extend vertically rather than horizontally. This effect is produced by viewing the tube from anormal viewing angle approximately ninety degrees to the position of viewing ordinary pictures directly normal to the reflecting member carried within the lid of the cabinet cover.

To provide for this type of viewing, Ihave'ar- The lower surface of this viewing atof 'alternatelyopaque and transparent strips or sections. At one end of' the grating member I have provided a reflecting member similar to the reflecting member carried within the cover of the cabinet for viewing optical pictures and have arranged this reflector so that it may be tilted to any desired and suitable angle'ior viewing puroses.

Reference maynow be made to the accompanying drawings, more specifically wherein there are several methods by which stereoscopic pictures may be transmitted are shown. By Fig. 3 a method which involves two separate transmitting cathode ray tubes I and 3 has been illustrated. In this arrangement the two transmitting tubes l and 3 are separated at substantially the same distance as the eyes, or approximately 2 inches apart, and the scanning line so arranged that the lines are scanned alternately as shown, for example, by Fig. 4 wherein the solid lines 5, for example, indicate the scanning path of tube I, whereas the dottedlines I, for example, indicate the scanning path of the tube 3 or, in other words, the. system is so arranged that the tube I, for example, may scan the'odd lines and the tube .3 scan the even lines. The circuit arrangement shown by Fig. 3 is provided for producing these results and in this figure the oscillator 9, for example, is arranged to transfer the generated oscillation frequencies, which are equal to the scanning line frequency, through the transformer H to the push-pull connected vacuum tubes l3 and I5 which are supplied with suit- I able bias upon the input electrodes thereof by means of a'biasing battery I I for example. Upon alternate half cycles one or the other tube is blocked completely and the other tube completely conducting. The output circuit of the pushpull amplifiers l3 and I5 is energized from a battery or power supply unit l9 connected with the output electrode through suitable resistors 2| for example. The output path from each inde-:

pendent push-pull amplifier tube l3and l5 leads through a suitable resistance couple to the input of a second pair of amplifiers 23v and 25 whose output energy is connected across the input circuit of the cathode ray tubes l, and 3 through resistors 21 and 29, so that the output energy. from the first tube -3 for example is connected between the cathode 3| and control. grid 33 of the scanning tube andthe output from the other amplifier 25 is connected across the oathode 35 andcontrol grid 31 of; the tube 3. this manner, as will be apparent from the showing in Figs. 7a. and 7b, the control grid electrodes 33 and 31- of the tubes .l and 3 are alternately biased above and below cut-oil so that the wave formation of Fig. 7a, for example, indicates the control on the tube '1 andi the wave formation shown as lb, for example, indicates the control on the tube 3, each of which is such that the tubes operate alternately, that is, while one tube )is biased to cut-ofi, the other tube is passing current so that one tube is able to scan while the other tube is'inoperative and vice versa.

In the arrangement of Fig. 3 the tubes I and 3 havebeen illustrated merely in a conventional manner and do not show the suitable deflectin fields for controlling the cathode ray nor show the anode potential supply to control the development of the cathode ray which is caused to scan the image pattern. By Fig. 9, however, a'

modification is shown wherein there is a cathode ray transmitting tube generally designated as A which corresponds, for example, to the tube l being of the, form disclosed by me in the application which I have filed jointly for Letters Patent in the U. S. as Serial No. 574,772 on November 13, 1931. In the form shown, the-scanning tubes A and B are adapted for any, general type and an anode member 39 serving to accelerate the electrons issuing from this source and tocause the pencil of electrons to scan the image area, I have arranged the control grid which'is adapted under the above mentioned condition to cut-oil completely the cathode ray.

,. As the cathode ray pencil 4| is projected from the anode member 39 it is controlled in its path by means of suitable deflecting fields shown conventionally as includingthe electromagnetic field 43 to control the horizontal motion of-the ray and an clectrostaticfield to control vertical motion of the ray. These fields are provided by means of the electromagnetic coils and the electrostatic plates and connected with a suitable source of energy fiuctuating'at desired frequency to control the rate of motion in either or .both of the desired deflecting directions.

The scanning ray pencil 4| having been suitably controlled in its vertical andhorizontal paths by the deflecting fields is arranged to impinge upon a light sensitive electrode 41 contained within thetube A for a purpose which was made apparent in my above referred to copending application.

To scan an image such as is indicated at 49,

this image is projected, for example, by a suitable optical system conventionally shown at 5| upon the light sensitive electrode 41 and produces :over the entire area of the electrode a space charge in the area between the 'light sensitive electrode 41 and the anode electrode '53. This space charge produced, which corresponds in electron density substantially to the intensity; of

light which is to be represented, .is released at each elemental area subjected to the. action of the cathode ray in its traversal of the light sen-- sitive electrode 41 so as to produce across the resister varying voltage drops which may be then amplified by a suitable amplifier 51 and conthat due to the cut-off action produced by the w oscillator 9 upon the cathode ray transmitting tubes and 3, there is a sequence of image signals first from tube A, then from tube B, then fromtube A and so on until the complete image is transmitted, after which the process is re- Y p eated. 1

Where desired for synchronizing purposes, each line of the image may be followed by a synchronizing signal as hasbeen indicated in application filed, for example, by an application otA. W.

Vance, Serial No. 544,959, filed June 17, 1931 and by an application of R. D.'Kell, Serial No. 565,953, fi ed September 30, 1931, so arranged the transmitte'd signals may appear as shown by Fig. 6 wherein the portions e indicate the image signals and the portions findicate the synchronizing signals which follow each series of image signals to produce at the point of reception synthesis of the received image.

In Fig. 7, portions c and d indicate the deflecting paths of the cathode ray 4| within the tubes A and B and illustrate conventionally a suitable saw-tooth path of scanning sothat the portions gof Fig. 70 indicate the time period when the scanning ray pencil 4| is active to scanning in the tube A and the portions g indicate the inactive or inoperative positions. Similarly in Fig.7d, the'portions h indicate the active or operative position of the scanning ray .pencil in the tube B and the portions h indicate the inoperative or inactivepositions of the scanning my pencil within this tube.

A modified arrangement of a transmitting sysv tem using a mechanical scanning device has been shown in Fig. 8 wherein a disc 83 adapted to rotate at suitable scanning speed about the shaft -or spindle 65 has been shown. This may be a 'single discs provided with two spirals or may be one disc with one spiral arranged as herein .shown; in the latter case the ordinary Nipkow disc is used and is so arranged that each hole or aperture 61 of the disc scans the same object 59, for example, twice through two separate optical systems 1| and 13 respectively which are separated one from the other by approximately the same separation as was suggested above for the transmitting tubes A and B.

The light reflected from the object 69 is then collected by anardinary system of photoelectric cells H which are placed symmetrically to both scanning systems and are connected through suitable conductors 13 to a transmitter which is similar to the usual television circuit arrangement.

A still further modification of the arrangement shown by Fig. 9, for example, is herein indicated conventionally by the arrangement of Fig. 5'

wherein'only a single transmitting tube such as the tube A is utilized. 'I'histube however has a special screen 4'! replacing the screen or. light sensitive area 41 shown in Fig/9 and is arranged so that the light from the object of subject of which the stereoscopic image is desired is projected on this double screen with a pair of matched objective lenses, as in the photographic camera. In the area between the two light sensitive areas 41 of the screen of Fig. 5, there is a narrow margin 48 which is not covered with light sensitive material and thisarea permits the'scanning of the image in such mannenthat at the receiving end the two separate images overlap each other. It is believed that full and complete illustration in addition to that shown by Fig. 5

. is unnecessary to a complete understanding of the invention.

To provide new for a suitable system by which the pictures transmitted in any of the'systems' ,of Figs. 5, 8 or 9 may be received, reference may :be had to a conventional illustration shown by Fig. 10 wherein the signals received upon a suitable form of receiving element 63, which may be either a wire line or a radio antenna, are then suitably amplified into the receiving amplifier 65. The image signals which are to portray in the receiving picture the efiects of light and shadow of the subject of which the image is produced are then transferred to a suitable form of receiving tubes 81 through the conductors 69 which are connected across the cathode II and a-control electrode or grid 13 of the image reconstructing tube 61. The cathode ray pencil in the form of an electron stream originating in the electrode 'II is then projected by accelerating electrode toward the fluorescent end wall I? of the tube 61 and is focused in suitabie'manner by means of an electrostatic field produced in the area between the anode I5 and a second anode 19 to which a voltage of the order of four times the voltage of the anode 15 is supplied.

Synchronizing signals transmitted from thepoint of transmission are then suitably selected as has been disclosed in the above mentioned application of R. D. Kell and by means of an amplifier 8! are suitably amplified and arranged to control the deflecting circuits 83 and 85 including the deflecting coils 81 and 89 respectively in which the former controls the vertical deflection of the cathode ray pencil and the latter controls the horizontal deflection.

In order to view the image produced on the fluorescent end wall TI of the viewing tube 61, the tube is arranged to extend vertically within a cabinet 9| which is provided with lid 93 capable of being pivoted along one edge hereof and having on its interior surface a reflecting member 95. These features have already been disclosedin my copending applicationlSerial No. 529,653 which was filed on April 13, 1931 and with an arrangement of this type the signals from the receiver-amplifier 65 when used to control the effective brilliahcy of the light spots produced upon the fluorescent .end wall of the cathode .ray receiving tube may be viewed in the reflector 95.

For stereoscopic television work it is, however, suitable, in order to obtain the effect of depth in the picture or, in other words, to obtain the effect of a relief picture, to'provide What has herein been termed an adapter 91 capable of being positioned directly above the viewingtube 61. The adapter has on its surface adjacent the fluoresoent'end wall 11 of the viewing tube 61 a grating it so arranged that the observer viewing the fluorescent end wall of the tube through the mirror surface 99 will see two sets of reconstructed image lines due to the construction of the grating and the position of the grating relativeto its point 'of observation sin-2e one eye of the observer will be unable to see certain portions of the fluorescent end wail 11 of the cathode ray image reconstruct= 5 ing tube 61 since,whereas these same particular portions will be observable to the other 'eye of the observer, but the portion ef the fluorescent end wall which were visiblejto the other eye will not be observed. Thus, the observer's right eye can observe certain portions of -the fluorescent end wall of the tube and other portions will be invisible or masked whereas the left eye will beable to observe the portions of the fluorescent end, wall of the tube which are masked with respect to the right eye, but the same portions visible to the right eye will be masked with respect-to the left eye of the observer.

With the grating 91 arranged in a vertical plane with respect to the field of view of the observer,

' the arrangement has been so provided that horitube is observed in the reflector 95 mounted with.

in the lid 93 of the cabinet 9]. Title field which the eyes of the observer can view when the grating '91 is interposed between the eyes of the observer and the fluorescent end wall of the tube is more particularly discernible from a further consideration of the showing of 1 where'the right eye'of the observer has been indicated bythe letter R and the left eye of the observer by the letter L, and the grating 91 is interposed between the observers eyes and the fluorescent screen "so that the observer's right eye can see the several areas or elemental strips of the fluorescent screen designated as I01 and the left eye of the observer will see the several areas or elemental strips generally designated as l09. From the combined combination of both of these sets of elemental strips, the observer is able to obtain an impression ofdepth in the resulting image on the fluorescent end wall of the tube.

I Where desired, sound signals may accompany the television signals and the sound and television signals may be reproduced simultaneously by producer I05 both being connected within the cabinet, these features have been shown and disclosed in my above mentioned copending-application Serial No. 529,653 and form, per se, I19 part of the present invention. Also is to be understood thatthe method of obtaining a sawtooth deflecticn of the cathode ray, per se, performs no part of my present invention only in so far as it cooperates with the remaining 'ele-' ments of the structure herein disclosed to produce the results desirable and while one suitable form of arrangement of producing this result has been set forth as being disclosed in the applica-' tion of A. W. Vance, Serial No. 544,959 it is, of

. virtue of the receiving tube 61 and the sound recourse, to be understood that other systems may 'be substituted and, for example, I may substi-- tute a system such as that shown in U. S. Patent No. 1,613,954, granted to D. A. Knoop. Also, it is within the scope of this disclosure to use a single distinct dynatron or glowrtube control for each separate scanning for so long as the frequency at which each tube operates is identical and then to the different paths of scanning bymeans of a cathode ray or mechanical commutator serving to connect each of the transmitting tubes in cyclic sequence with the transmitting channel where the frequency of the sequence is the same as the frequency .of each line of scanning.

In the event that the subject is scanned along a series of vertical paths'at the transmitter the slotted portions of the grating-9! in the minor reflector 95 carried in the 93-of the cabinet 9| which supports the viewing tube.

Thisinvention has been illustrated only in av general preferred form thereof but it should be understood that it is capable of many and varied modifications without departing from its spirit entitled to make and to use any and all of these modifications such as suggest themselves to and scope, and I therefore believe myself to be those skilled in the art to which the invention is directed, providing of course that such modificareceiving station responsive to the signal currents I of each of the plurality of transmitter scanning devices and adapted to reproduce in the sequence of the transmitting station the scanning paths, and a grating interposed between the image reconstructing device and an observer thereof so that the image reconstructing device when viewed through the gratingv appears to represent a threedimensional image of the subject located at the point of transmission.

2. In stereoscopic television apparatus, a plurality of electronic scanning tubes in each of which there is produced an electronic beam for scanning a produced electrical image of a subject of which a stereoscopic image representation is to be produced, means for scanning the sub-- ject by each tube along a series of substantially parallel paths, and a single means for controlling the electronic beams of both tubes so as to cyclically render one tube operative to scan and the other tube inoperative to scan so that alternately adjacent paths of scanning are scanned by different tubes.

3. Television apparatus for producing stereoscopic television images which comprises a cam ode ray image reconstructing tube, means for controlling the observable light intensities produced on the fluorescent end wall of the cathode ray tube in accordance with received signalling impulses and a grating positioned adjacent the fluorescentend wall ofthe tube, said grating being so positioned that the solid portions thereof extend in paths coinciding substantially with the paths of image point reproduetion'within the tube, a light reflecting image viewing surface positioned to receive the light passed through said grating by the light developed upon the fluorescent viewing wall of said tube, said grateoscopic television image signals, a cabinet having supported subing also being so positioned relative to an observer of'the light intensities appearing on the fluorescent end wall of the tube and'said light reflecting viewing surface that the resulting fluorescent effects produced by the signals are observed in such manner that the reconstructed image, appears to have depth.- V

4. In television apparatus for producing sterimages from transmitted stantially vertically therein a cathode ray image reconstructing tube, means for moving the cathode ray developed to trace the tube fluorescent screen according to apreestablished pattern along a series of parallel paths, means for impressing the transmitted signals upon the cath-' ode ray tube to cause intensity controlled light spots to appear. upon the fluorescent end wall thereof as saidseries of parallel paths are traversed, a grating supported upon. th'ecabinet and spaced apart from the end wall of the tube by a predetermined distance, said grating havingjthe solid portion thereof extend along paths coinciding substantially with the paths of. image point reproduction in the tube, and a reflecting element associated withthe grating so that an observer viewing the reflectingelem'ent observes the fluorescent eflects on the tube end wall thro'ugh the grating. whereby the effects of depth stantially vertical therein a cathode ray image reconstructing tube, means for causing the cathode ray developed to scan the fluorescent screen of the: tube according to a preestablished pattern of selected parallel paths, means for impressing the transmitted signals upon the cathode ray tube to-cause intensity controlled light spots to appear upon the fluorescent end wall thereof along the selected series of parallel paths; a grating supported within the cabinet and having the solid portion thereof extend along paths coinciding substantially with the paths 'of image point reproduction in the tube, and an angularly tiltable reflecting element associated with the grating so that an observer viewing the reflecting element observes the fluorescent eflects on the tube end wall through the grating whereby, the effects of depth in the reconstructed image on the tube end wall are apparent due to thetact that the solid sections of the grating obscure predetermined pathsot image point reproduction to each eye .of the observer. W

6. In television apparatus for producing stereoscopic television images from transmitted image signals, a cabinet having supported substantially vertical therein a cathode ray image reconstructing tube, means for causing the cathode ray developed within the-tube to scan the fluorescent end wall thereof along a predetermined selected series or substantially parallel paths, means for impressing the transmitted signals upon the cathode ray tube to cause intensity controlled light spots to appear upon the fluorescent end wall thereof along the selected series of parallel paths, a grating element supported within the cabinet and having the solid portion thereof extend along paths coinciding substantially with the paths orimage point reproduction in the tube, and a reflecting element associated with the grating so that an observer viewing the reflecting element observes the fluorescent effects on the tube end wall through the grating whereby the effects of depth in the reconstructed image on. the tube end wall are apparent due to thefact that the solid sections of the grating obscure predetermined paths of image point reproduction .to each eye of the observer.

7. Television apparatus for producing stereoscopic television images which comprises a cathode ray image reconstructing tube, means solid portion thereoi extend in paths coinciding substantially with the paths of image point reproduction within the tube positioned at a prede 'termined location between an observer of the light intensities appearing on the fluorescent end wall of the tube and the tube so that the resulting fluorescent eflects produced by the signals are servation.

observed'in such manner thatthe reconstructed image'appears to have depth, and a reflecting device m whichthe image representations pro-- duced upon the fluorescent end wall of the tube as passed-by the grating are reflected for ob- 8. In stereoscopic television apparatus, a pinrality of electron beam scanning tubes each for scanning a subject'of which a stereoscopic image representation is to be produced, means for scanning the subject of each tube along a series of substantially parallel paths; a; control element provided in. each tube to control the scanning operation, andea single means for biasing the control element of each tube so as to cyclically render one tube operative to scan and the other tube inoperative to scan whereby adjacent and successive scanning paths are produced by different scanningitubes.

9. In television apparatus, a plurality of scanning tubes each'including a photoelectric surface adapted to have projected thereon a view of the subject to be televised, means forlprojecting a view of the subject on each of said surfaces, means for scanning said photoelectric surfaces .line by line sequentially, means for developing v signals representative of the light values on each of the photoelectric surfaces for each line scanned, and means for developing a synchronizing signal in the interval between the sequential scanning of a single line on eachof said surfaces.

10. In television apparatus, a plurality of spaced scanning tubeseach containing a photoelectric surface adapted to have projected thereon a view of the subject to be televised,means for projecting on each of said surfaces an image representative of the subject viewed with an average spacing equal to the spacing of human 'eyes,

means for scanning said photoelectric surfaces line by line sequentially, means for developing signals representative of the light values on each of. the photoelectric surfaces for each line scanned, and means'for developing a synchronizing signal in the interval between the-sequenfaces.

tial scanning of a single line on each of said sur- 11. In television apparatus, a plurality of spaced scanning tubes each containing a photoelectric surface adapted to have projected thereon a view of the subject to betelevised, means to project on each of said surfaces an image representative of the subject viewed with a spacing equal to approximately two and'a half" inches, means for scanning said photoelectric surfaces line by line sequentially, means for developing signals representative of the light values on each of the photoelectric surfaces for each line scanned, and means for-developing a synchroniz- 'ing signal in the interval between the sequential scanning of a single line on each of said surfaces.

12. In television apparatus, a plurality of noncontiguous laterally separated photoelectric surfaces adapted to have projected thereon a view of the subject to be televised, means for projecting a view of the subject on each of said surfaces, means for scanning said photoelectric surfaces line by line sequentially, means for developing signals representative of the light values on each of the photoelectric surfaces for each line scanned, and means for developing a synchronizing signal upon the completion of the scanning of the image on all of the photoelectric surfaces.

13. In television apparatus, a plurality of noncontiguous laterally separated photoelectric surfaces adapted to have projected thereon a View of the subject to be televised, means for projecting a view of the subject on each of said surfaces, 

